Engine-starter



W. L. IVECGRATH.

ENGINE STARTER.

APPLICAHON FILED APR.9.1919.

1,348,289. Patented Aug". 3, 1920.

2 SHEETS-SHEET l* W. L. McGRATH.

ENGINE STARUER. lAPPLICMWON FILED APR.9.1919.

Patented Aug. 3, 1920.

2 SHEETS-SHEET 2.

@ y Wad@ UNITED STATES PATENT OFFICE.

WILLIAM L. MCGRATH, OF ELMIRA, YRK, ASSIGNOR TO ECLIPSE MACHINE COMPANY, OF ELMIRA, NEW YORK, A CORPORATION OF NEIV YORK.

ENGINE-STARTER.

Specification of Letters Patent.

T0 all 'whom 'it may concern:

Beit known that I, WILLIAM L. MCGRATH,

a citizen of the United States, residing at Elmira, in the county of Chemung and State of New York, have invented certain new and useful Improvements in Engine-Starters, of which the following is a specification.

My invention relates to a starter for an engine such as an internal combustion engine, and pertains more particularly to the drive or transmission thereof for automatically connecting the starting motor or other source of power to a member or part of the engine to be started and for thereafter transmitting the power thereto for the starting of such engine.

My invention is embodied in the present instance in a structure of the type known as the Eclipse-Bendix type of drive characterized by the employment of a rotatable member such as a screw shaft and a driving member mounted thereon for longitudinal movement thereof and. rotaryl movement therewith and adapted to be connected either directly or indirectly with the engine member. The object of my invention is to produce a structure of this type of novel and efficient construction and mode of operation and characterized further by compactness particularly as to its transverse dimension or diameter in order to accommodate comparatively small clearances provided in certain installations on automobiles. Various features of advantage and utility in my construction will be apparent from the description hereinafter given.

In the drawing Figure l is a sectional elevation of a starter embodying my invention; Fig. 2 is a section of the driving member or pinion detached; Fig. 8 a sectional elevation of the parts shown in meshed or driving position; Fig. 4 a sectional elevation of a modified form of construction; and'Fig. 5

. a section on the line 5-5 of Fig. 4.

For the purpose of a clear and definite description of my invention I have shown one specific embodiment thereof according to which the same is direct-driven by a starting motor although it will be understood that it may be indirect-driven thereby and also that other starting means such as hand power may be employed.

s shown, the starting motor indicated at A has an extended armature shaft 1 having 'tions of such or not as desired an outer bearing 2 and provided with a screw-threaded portion at its outer end formed by the threads l and the plain portion lb at its inner end and with an annular projection 1c intermediate its length and separating said two porshaft. This screw shaft constitutes a rotatable member and forms the support and also the driving means for the driving member which is here in the form of a pinion 3. This pinion is screwvthreaded upon the screw shaft and thereby so mounted as to move longitudinally intok mesh with the teeth of the engine member such as the iiy wheel 4i, after which it will partake of the rotary movement of its shaft.

Upon the plain portion of the shaft there is loosely mounted a follower which is in the form of a 'collar 6 operatively connected with the pinion by a. yielding connection in the form of a coiled spring 7 the ends of which are connected with the pinion and follower respectively, and operating as an extension spring. Thisl spring is attached at its ends in any suitable manner, as by threading the end coils of the spring onto correspondingly threaded extensions of such parts. i

Between the follower and the fixed abutment provided by the plate 8 at the side of the motor frame is a light coiled spring 9 the inner end of which bears against the follower indirectly through the anti-friction thrust bearing 10.

By preference in this construction, I make the threads of the shaft and pinio'n shown in the drawing, according towhich the threads 1El are spaced apart a distance -considerably in excess of the width of thev threads 3a of the pinion, with the result that such pinion is capable of a longitudinal backward movement on the screw. shaft equal to the difference between the groove space in the screw shaft and the width of the pinion thread, this longitudinal movement being in a direction opposite to that of the longitudinal advance movement of the pinion or meshing purposes. In order to hold the front edge of the plinion thread against the rear edge of the s aft thread the light springt), above mentioned, is employed, the same normally transmitting its tension through the follower and spring 7 to the pinion 3, this spring 9 also serving to receive the impact Patented Aug. 3, 1920.

l condition.

vances longitudinally until its left-hand end of the pinion and its associated parts in the demeshingv operation.

Describing a cycle of operation and starting with the parts in their normal position as shown in I* ig. '1, when the motor is operated and the shaft l thereby rotated the pin-- yion 3 is automatically advanced longitudishaft 1, thev anti-friction bearing followingl up the advance of this lcollar by reason of the pressure of the spring 9 which, at the beginning of this operation, is in a compressed This collar or follower 6 adcomes into contact with the stop collar 1, whereupon its further advance movement is arrested. However, the pinion which is already in mesh with the fly wheel (because it has already reached and meshed with the fly wheel before the follower has reached 'the stop collar 1c) continues to advance longitudinally owing to the screw action of the shaft 1, but against the tension of the spring 7 which now becomes extended. The parts now assume the relative position shown in Fig. 3. If the spring is made of suilicient resistance .the load may be yieldingly transmitted entirely therethrough inasmuch as in such case the pinion would not come into Contact with the stop nut 5, or if desired the construction may be such that the normal load or resistance of the engine may be taken by the spring` 7 and the increased amount caused by an abnormal load may be taken by the stop nut 5. In Fig. 3 I have shown the position of the parts in the driving operation in which the load is carried by the spring 7 the pinion not being in contact with the stop nut. In the demeshing operation the spring 7 will assist in the Y'return of the pinion to its normal "position,

and the spring 9'will againbecome compressed as shown in Fig. 1 inorder to hold the s'crewthreads into engagement with each other.

In the .event that the pinion teeth should abut the ily wheel teeth end to end the pinion will be momentarily stopped but the screw shaft will Acontinue to rotate without immediate action on the pinion, such relative movement between the shaft and the pinion being against the tension more particularly of the spring 9, which thus absorbsany shock of said impingement of the pinion. The continued rotation of the screw shaft while the pinion is in contact with the fly wheel teeth will cause a slight movement of the pinion rotarily and thereby bringv it into perfect register with the ily wheel teeth, which will result in meshing therewith, whereupon the driving operation wil-l take place as above explained. A

In Figs. 4 and 5 there is shown a modilied form of construction in that the screw shaft and pinion have the ordinary threads and such shaft is of the sleeve or hollow shaft type. The screw shaft is la sleeve mounted on the driving shaft and operatively connected therewith for rotary movement therewith and limited. longitudinal movement thereof. As shown, this screw shaft has a screw threaded portion 11, a plain portion 12 and an enlarged portion or annular projection 13 intermediate its length. The shaft or sleeve is keyed to the driving shaft through the medium of the key 14 in a key-'socket in the shaft 1 and in the longitudinal key-way 16 in the bore of the sleeve., The pinion 17 is screw threaded on this shaft and adapted to mesh with the fly wheel 4. Upon the plain portion 12 of t-he shaft there is mounted a follower 18 in the form of a collar adapted to vslide on such shaft. This follower is operatively connected with the pinion by means of a Ayielding connection, preferably a coiled driving spring 19, fastened at its ends to the follower and pinion respectively and operating as an extension spring.

The mode of operation of this modified form is the same as the one above described, except that in the event of the abutting of the teeth end to end the screw shaft does not stay in the same osition axially but moves axially or long1tudinally to relieve the shock of such abutting. This longitudinal movement to the right is yieldingly resisted by the light coiled spring 20 interposed between the anti-friction bearing 21 at the end of the screw shaft and the plate or washer 22 bearing against the outer bearing 23 of the driving shaft.

I claim:

1. An engine starter drive including a rotatable member, a driving member mounted thereon for longitudinal movement thereon and rotary movement therewith, a follower loosely mounted on the rotatable member and yieldingly connected with the driving member, and means for stopping the movement of the follower before the end of the said longitudinal movement of the driving member.

2. An engine starter drive including a rotatable member, a driving member mounted thereon for longitudinal movement thereon and rotary movement therewith, a follower loosely mounted on the rotatable member, a spring connecting the driving member and the follower, and means for stopping evs the movement of the follower before the end of said longitudinal movement of the driving member.

3. `An engine starter 'drive including a rotatable member, a driving member mounted thereon for longitudinal movement thereon and rotary movement therewith, a follower loosely mounted on the rotatable member, a coiled spring encircling the latter and connected at its ends respectively with the driving member and the follower, and means for stopping the movement of the follower before the end of said longitudinal movement of the driving member.

4. An engine starter drive including a rotatable member, a driving member mounted thereon for longitudinal movement thereon and rotary movement therewith, a follower loosely mounted on the rotatable member, a spring connecting the driving member and the follower, said rotatable member having an enlargement intermediate its length forming a stop for stopping the longitudinal movement of the follower before the end of said longitudinal movement of the driving member. .l

5. An yengine starter drive including a rotatable shaft having a screw threaded portion at one end and a plain portion at the other end, and also having an enlargement intermediate said portions, a driving member threaded on-said threaded portion of the shaft, a collar loosely mounted on said plain portion, a spring connecting the driving member and the collar, 'said enlargement acting as a stop for the longitudinal movement of the collar before the driving member has completed its longitudinal movement in the same direction.

6. An engine starter drive including a rotatable member, a driving member mounted thereon for longitudinal movement thereon and rotary movement therewith, a. follower loosely mounted on the rotatablemember and yieldingly connected with the driving member, means for stopping said longitudinal movement of the follower before the end of the said longitudinal movement Vof the driving member, and a yielding thrust bearing for such follower.

7. An engine starter drive including a rotatable shaft having a screw threaded portion at one end and a plain portion at the other end, a driving member threaded onv said threaded portion of the shaft, the shaft threads being lseparated a -distance materially in excess of the width of the threads of the driving member to permit of longitudinal movement of the latter, a collar loosely mounted on said plain portion of the shaft, and o eratively connected with the driving mem er, and means for yieldingly holding the threads of the shaft and driving member in contact.

8. An engine starter drive including a rotatable shaft having a screw threaded portion at one end and a plain portion at the other end, a driving member threaded on said threaded portion of the shaft, the shaft threads ybeing separated a distance materially in excess ofthe width of the threads of the driving member to permit of longitudinal movement of the latter, a collar loosely mounted on said plain portion of the shaft, and operatively connected with the driving member, and a spring coperating with said collar and transmitting compression therethrough to the driving member to hold the threads of the shaftA and driving member in contact.

9. An engine starter drive includinga rotatable shaft having a screw threadedv portion at one end and a plain portion at the other end, a driving member threaded'on said threaded portion of the shaft, the shaft threads being separated a distance materially in excess of the width of the threads of the. driving member' to permit of longitudinal movement of the latter, a collar loosely mounted on said plain portion of the shaft, and operatively connected with the driving member, a4 spring arranged on the shaft land bearing at one end against a fixed element and having its other end .cooperating with Vsaid collar.

10. An engine starter drive including a rotatable shaft having a screw threaded portion at one end and a plain portion at the other end, a driving member threaded on said threaded portion of the shaft, the shaft threads being se arated a distance materially in excess o the width of the threads of the driving member to permit of longitudinal movement of the latter, a collar loosely mounted on said plain portion of the shaft, and operatively connected with the driving member, and an anti-friction bearing coperating with such collar.

11. An engine starter drive including a rotatable shaft having a screw threaded portion at one end and a plain portion at the other end, a "driving member threaded on said threaded portion of the shaft, the shaft threads being separated a distance materially in excess of the width of the threads ofthe driving member to permit of longitudinal movement of the latter, a collar loosely mounted on said plain portion of the shaft, and\ operatively connected with the driving member, a spring arranged on the shaft and an anti-friction bearing between thespring and collar.

12. An engine starter drive including a rotatable member, a driving member mounted thereon for longitudinal movement thereon and rotary movement therewith, a follower yieldingly connected with the driving member and having a corresponding longitudinal movement, and means for stopping such movement of the follower before the end of said longitudinal movement ofthe driving member. l

13. An engine starter drive including a rotatable screw shaft, a pinion screw-threaded thereon for longitudinal movement thereon and rotary movement therewith, a follower vieldingly connected withV the inion and aving a corresponding longitu inal .movement, and means for stopping .such move- 10 ment of the follower before the end of such longitudinal movement of the pinion.

14e` An engine starter drive including a ro-v tatable 'shaft havin a screw-threaded porrially -in excess o the width ofthe threads f of the driving member to permit of lon itudinal movement of the latter, and a co ar loosely mounted on 'said plain portion of the shaft7 and operatively connected with the driving member.

' WILLIAM L. MGGRATH 

